You created some mood with darkness of this photo. Compositionally there seems to be alot of empty space. I like the idea of a vertical frame for the shot, with the edges to either side of the large light reflection on the water. But then again that may take away from the horizontal lines of the photo.
Very pretty, but a bit too blue for my taste. The blue saturation you have here carries over into the mountains, giving an unnatural feel to the shot. Perhaps if you did the same treatment again, but masked/reduced the effect on the mountains?